I think it should be encouraged to make healthy breaks during very long runs.

I know there are already rules for games like Forgotten Lands so it shouldn't be too different.

Also for the very long Main Series RTA i think a longer sleep-break should be okay.

There was a discussion about this over the past summer in regards to sleep breaks / timer pauses for longer categories including the Multi-Kirby board, this was around the time of the 2023 Classic Titles Race. No consensus was reached but I agree, I think this is something that should be discussed more and proper rulings for these breaks should be added. Using the KFL rulings would be a good start.

Has anyone thought of doing a Switch Trilogy 100% Speedrun?

Don't worry, It will come with healthy Breaks! ;)